Boris Johnson not Theresa May should appoint new UK ambassador to US, says ally Liz Truss

Boris Johnson and not Theresa May should appoint Sir Kim Darroch’s successor as British ambassador to the US, a key supporter of the Conservative leadership favourite has claimed.

Chief Secretary to the Treasury Liz Truss, who hopes to be promoted to chancellor under Mr Johnson, said recruiting a replacement for Sir Kim would take months and so it should be a job for the new prime minister.

Her warning shot to the outgoing PM comes as a fierce battle rages between allies of Mrs May and those of Mr Johnson over who should appoint Sir Kim’s successor.

Speaking to political journalists at Westminster, Ms Truss said: “The permanent secretary at the Foreign Office has been clear that this is a job that is going to take months rather than weeks to recruit for.

“So I think the question is academic. It’s likely that the new US ambassador will be selected and appointed by the new prime minister.”

Since Sir Kim quit, Mr Johnson’s supporters have warned Mrs May it would be unacceptable to tie the hands of her successor by appointing a new ambassador in one of her final acts in Downing Street.

But ministers loyal to the prime minister want her to move swiftly to appoint a replacement to deny Mr Johnson making the decision.

They claim the role is too important to be left vacant for an extended period and point out that Mrs May’s predecessor, David Cameron, appointed Ed Llewelyn, his chief of staff, as ambassador to France shortly after saying he was leaving Number 10.

A Downing Street spokeswoman has said, however, that Mr Cameron suggested Mr Llewelyn and Mrs May then approved the appointment when she succeeded him as prime minister in 2016.

Sir Kim stepped down after a leak of diplomatic memos in which he spoke critically of Donald Trump and his administration – prompting the furious reaction of the US president.

Questioned about Mr Trump’s highly personal and critical tweets about Sir Kim and Mrs May’s Brexit strategy, Ms Truss said: “I’m a patriot, so I don’t like to hear any foreign leader slagging off our government.

“But fundamentally, whatever the rights and wrongs of the issue, a [Brexit] deal has failed to get through on numerous occasions.

“It’s a dead duck, so we now need a fresh approach, it’s more urgent than ever before.

“The British public has lost huge trust in politicians and that is why we need to deliver by 31 October.”

Ms Truss also attacked ex-prime minister Sir John Major after he said he was prepared to go to court to stop Mr Johnson suspending parliament – known as “prorogation” – in order to force through Brexit by 31 October.

“I remember when John Major complained that Margaret Thatcher was trying to be a back-seat driver to his government and I believe he should take his own advice,” she said.

Ms Truss said prorogation should be considered by whoever succeeds Mrs May.

“What I believe in this stage of negotiations is that it’s vital not to close off any avenues,” she added.

“I don’t want to see these arcane techniques used, but nor do I want to have a conversation which gradually boxes in the government of the day in delivering what the British people want.

“It’s not something I would like to see, but I think it’s very important not to box off options.”

In a highly confident and witty speech, which was seen as a very public audition for the job of chancellor, Ms Truss said Mr Johnson had the “vim and verve” to be prime minister and was the “insurgent” in his battle against his rival Jeremy Hunt, the foreign secretary.

Making no secret of her own ambition, Ms Truss said she was “not yet in Number 11”, but she wanted to be “in the engine room of the British economy” in her next post.

And suggesting that fellow Johnson supporter Jacob Rees-Mogg might succeed her as chief secretary, she said: “As outgoing chief secretary, I leave the public finances in good shape – the deficit is now down to 1%, the lowest since 2002.